Predator Rats
The predator rats are a group of carnivorous rodents from Dougal Dixon's After Man. They evolved from rats, hence their names. After the Age of Man, the extinction of most carnivorans gave rats a chance to take over their niches. In the distant future, they diversified, having to take the place of the ordinary mammalian carnivores - lions, tigers, wolves, weasels, and even seals and walruses - and evolved a similar form, although they have retained primitive features, like a long hairless tail. They have become Earth's principal carnivorous mammals. History of Predator Rats :In the mammal world the predators were traditionally carnivorans - specialized meat-eating placental mammals with teeth modified for stabbing, killing and tearing flesh. Their legs were designed for leaping and producing a turn of speed that could quickly bring their chosen prey within killing distance. Wolves, lions, saber-toothed cats, stoats - these were the creatures that fed on the docile herbivores and kept their numbers in check both during and before the rise of humanity. However, being very specialized, these species tended not to have a great lifespan. They were so sensitive to changes in the nature and the populations of their prey that the average life of a carnivoran genus was only 6.5 million years. They reached their acme just before the age of human rule, but have since decreased in importance and are now almost extinct except for a number of aberrant and specialized forms found in the coniferous forests of the far north and in the South American island continent. :The place of most of the carnivorans, as the principal mammal predators, is now occupied by a variety of mammal groups in different parts of the world. In temperate regions the descendants of particular rodents occupy this niche. :When the carnivorans were at their peak, the rodents, particularly the rats, began to acquire a taste for meat and animal waste. The spread of humankind to all parts of the world encouraged their proliferation and after humanity's demise they continued to flourish in the refuse created by the disruption and decay of human civilization. It is this adaptability that has ensured their survival. :Despite the specialized nature of their teeth, rats were able to live on a wide range of foods. At the front of their mouths they had two sharp gnawing incisors, which continued to grow throughout life to compensate for wear and which were separated by a gap from the back teeth. These were equipped with flat surfaces for grinding vegetable matter. This is very different from the typical carnivore dentition, which had cutting incisors at the front followed by a pair of stabbing canines and a row of shearing teeth at the back. :As the rats expanded to occupy the niches left by the dwindling carnivorans their teeth evolved to fulfil their new role. The gnawing incisors developed long, stabbing points and were equipped with blades that could cut into and grip their prey. The gap between the incisors and the back teeth became smaller and the grinding molars became shearing teeth that worked with a scissor action. To make the dentition effective the jaw articulation changed from a rotary grinding motion into a more powerful up-and-down action. This dentition was crucial in the development of the predator rats and allowed them to radiate into the numerous forms and varieties seen throughout the Posthomic world today. Species of Predator Rats The falanx (Amphimorphodus cynomorphus), the commonest species of predator rats found in temperate latitudes and the largest member of the family. Although superficially doglike in form, its rat ancestry is quite unmistakable. The falanx are the rabbucks' principal predators (especially for common rabbucks). They hunt in small packs, singling out the weaker individuals and harrying them to exhaustion. In temperate latitudes of the Northern Continent the larger herbivores, the grazers and browsers of the plains and forests that were one time prey to the wolf, have now become the prey of the pack-hunting falanx. The evolution of this form involved the modification of the limbs from the fairly generalized scampering legs of the rat to very sophisticated running organs with small, thickly padded feet, and long shanks powered by strong muscles and tendons. The rapide (Amphimorphodus longipes), a native of the northern temperate plains of Europe and Asia, is built for speed. Its highly flexible spine gives it the added impetus to reach speeds of over 100 kilometers per hour. The temperate ravene (Vulpemys ferox), a Eurasian species about the size of the extinct red fox or wildcat and preys on smaller mammals and birds. It has long claws and pointed stabbing fangs. The polar ravene (Vulpemys albulus), an Arctic tundra species that is the meachings' principal predator, about the size of the extinct arctic fox and very different from its temperate woodland cousin, the temperate ravene. It has a small head with tiny eyes and ears (an adaptation that prevents frostbite) and long, dull brown fur that turns white in the winter to camouflage it against the snow. It attacks meachings by digging into their fortresses with its front paws. In early autumn the polar ravene moults its dull summer coat and grows a thicker creamy-brown covering of fur. Although the polar ravene is larger than the ravene of the temperate woodlands, it has smaller facial features. The janiset (Viverinus brevipes), a long-bodied, burrowing predator, strongly resembling the ext inct stoats and other weasels, and like them will swim, climb trees and tunnel underground in pursuit of its prey. The bardelot (Smilomys atrox), a migratory species from the Arctic tundra that would have been very much at home back in the last glacial period. With the advent of the gigantelopes the saber tooth pattern reappeared in predatory mammals, but this time among the predator rats. The bardelot, unlike other members of the group, exhibits sexual dimorphism in that only the female is equipped with sabre teeth (formed from the outer crowns of her two front teeth), a pouch for them, and hunts the woolly gigantelopes. The male, having none, resembles more the polar bears that once inhabited these latitudes. Plausibility The existence of predator rats has been strongly criticized. Dixon eliminates almost all carnivores--including coyotes, which are effectively impossible for humans to eradicateFraser, Caroline. (1999). Rewilding the World: Dispatches from the Conservation Revolution. New York City: Metropolitan Books.; cats, which are some of the most invasive species everThe Commonwealth of Australia. (2011). The Feral Cat (Felis catus) - Fact Sheet. Retrieved from http://www.environment.gov.au/biodiversity/invasive/publications/pubs/cat.pdf. and are well liked by humans; and the American mink, which are listed by the IUCN as Least Concern and stableReid, F. & Helgen, K. (2008). Neovison vison. Retrieved from http://www.iucnredlist.org/details/41661/0.. Not limiting ourselves to North America, we find many other species that would have to be driven extinct, many of which are doing perfectly well. References Category:After Man species Category:Animals Category:Mammals Category:Rodents Category:Placentals Category:Europe Category:Asia Category:North America